This project is designed to investigate the relationships between chemical structure and the solution conformation of complex carbohydrate polymers, such as those that occur at eucaryotic cell surfaces, in the conective tissue of the higher organisms, and in the extracellular capsules and slimes of various microorganisms. Attention will be focussed on the extracellular microbial polysaccharides, many of which are immunogenic and essential for microbial infection of the host organisms. Quantitative measurements of various macromolecular solution properties will be carried out. In particular, spatial and geometric features accessible directly from light scattering and high resolution nuclear magnetic resonance experiments will be investigated. These characteristics are also calculable quantitatively from detailed and realistic molecular models using theoretical methods of conformational analysis and statistical mechanics. Agreement between observed and calculated results can engender confidence in the physical reality of the molecular models employed. Reliable polysaccharide chain models may be used, often in conjunction with computer graphics techniques, to understand the structure-conformation relationships in general and to identify the energetically preferred conformations of the complex carbohydrate polymers. such conformational information is essential to an understanding of the intermolecular interactions that mediate the biological function of many of these materials.